Molded roof structure and its production



M y 27, 1952 R. w. RUMBLE 2598,60?

I MOLDED ROOF STRUCTURE AND IT'S PRODUCTION Filed June 14, 1945 3 Sheets-Sheet 1 mlvszvrak P0) MLUAM lPl/MJAE drraaruey Rfw. RUMBLE MOLDED ROOF STRUCTURE AND ITS PRODUCTION Filed June 14, 1945 May 27, 1952 3 Sheets-Sheet 2 E /A/VENTUR Par MAL/Alf Pmazs mjmaa.

May 27, 1952 R. w. RUMBLE MOLDED ROOF STRUCTURE AND ITS PRODUCTION 3 Sheets-Sheet 3 Filed June 14, 1945 MVEA/I'M For W/u m x W A rramvs v Patented May 27, 1952 UNITED OFFICE -MOLDED ROOF STRUCTURE AND ITS PRODUCTION Roy William Rumble, Pretoria, Transvaal, Union of South Africa Application June 14, 1945, Serial No. 599,427

, In the Union of South Africa July 7, 1944 Claims.

- 1 This invention relates to concrete roofs; the term concrete being used in this specification to I include any appropriate material that is moulded in a plastic condition and subsequently sets or is caused to set as a solid mass.

It is customary to construct fiat concrete roofs both by the assembly of pre-cast components, including beams and slabs; and by moulding the whole roof in position from plastic concrete.

In the case of pitched roofs constructed wholly or partly of concrete the present practice includes the procedure of pro-casting all the components including pre-cast rafters, hoisting said components into position and there assembling them. It also includes the procedure of moulding a horizontal ceiling slab or horizontal beams in place; pre-casting the components-including rafters-that support the roof covering, precasting the roof covering, hoisting the separate pre-cast elements into position and there assembling them.

An object of the invention is to cheapen and simplify the construction of a pitched concrete roof by moulding plastic concrete in position.

The present invention consists in a pitched roof comprising a number of members, herein referred to as raftermembers, that are spaced apart horizontally. Such rafter members are constructed to perform the function of supporting roof covering at the pitch inclination above spaced roof supporting means such as walls. The roof further comprises web formation that extends between and connects said rafter members; and both the rafter members and. the web formation are formed of concrete moulded in position in the roof.

The form of the web formation may be varied. In one form it consists of a ceiling slab supported on the roof supporting means and extending between the lower parts of the rafter members. In another form it is the roof covering, supported by the rafter members beneath it. In another form the web formation consists of a number of vertical stabilizing webs extending from. one rafter member to the other.

In most forms of roof according to the invention the rafter members extend in the direction in which the roof is inclined and rest at their ends directly or indirectly on the spaced walls or equivalent roof supporting structure. The rafter members of the invention are usually shaped to have the general triangular form in outline as an ordinary roof truss or principal. They may be solid triangles but it is preferred to core out portions within the. triangular pcriphery; and the coring may be arranged to produce a monolithic rafter member having a close resemblance in shape to the ordinary builtup truss comprising rafters, a king post, a tension chord, and struts.

The roof covering that is supported by the rafter members may be of any desired kind of sheet material and where necessary purlins are mounted on the transverse rafter members to support such sheet material. However it is a desirable feature of the invention that the roof covering also is moulded in position on the rafter members; and preferably so as to be monolithic with said members.

The invention further consists in a process of erecting a pitched roof which comprises concrete roof covering cast on supporting structure such as rafter members above specified. Said process consists in erecting deck shuttering for the roof covering, and casting the roof covering on said deck shuttering while leaving aperturing in the roof for the extraction of the deck shuttering. The deck shuttering is then lowered to part it from the cast roof covering, and the deck shuttering is withdrawn piecemeal through the aperturing.

The aperturing through which the shuttering is Withdrawn may be at the ridge of the roof; and this is particularly the case'when the abovementioned ceiling slab provides eaves soffits. Said ridge aperturing is subsequently closed by placing ridge covering structure in position.

Examples of roof structure according to the invention are shown in the accompanying drawings in which- Figure I is a perspective view showing a portion of the walls and the concrete pitched roof of a building,

Figure II shows the same, but with rafter members of a different form.

Figure III shows a roof with a hipped end.

Figure IV shows a roof without a ceiling slab.

Figure V shows a modification of the structure that supports the roof-covering.

Figure VI shows a lean-to roof.

Figure VII shows shuttering for moulding the rafter members.

Figure VIII shows a core block.

Figure III shows shuttering for moulding the roof covering.

Figure X illustrates the removal of shuttering from the interior of the moulded roof.

Referring to Figure 1, 2, 2, indicate walls of the building and 3 indicates a concrete ceiling slab mouldedin place and so as to be supported 3 tern-1g 25 or say suitable liind is ino'ii'ri 3 by the walls 2. 4 indicates a number of rafter members moulded in position and extending upwardly from the said slab 3. The said members 4 are in outline of the same general triangular form as an ordinary timber roof truss and they perform the same functions as such a truss; that is'they actas'bea'ms spanning: the 'wallsf2 and provide the "sloping upper edges 5 on which roof covering 6 is supported at the pitch angle of the roof. The roof further includes said roof covering 6, which is a concrete deck sloping down two Ways from the ridge I and inade'of concrete moulded in position.

Included in the roof shown, "arethe gables 3 which in the well known manner constitute' a f portion of the gabled walls 9' of the building and are not part of the presentinveiitionffiui'ifier the moulding of the members 4, reinforcement I is left projecting from their upper edgesi'fo'r Figure II shows another 'form of'the roof in which the cored aperturing iSso'shaped'that each a; rafter member4 has the same' general'appearahce and formation as an ordinary roof'trussy'so as to compriseelements ls, l4, I5, l'fiporresponding respectively to the rafters, the 'tie, -the-king post and struts of a built-up truss;"all*such*elew ments [3 to [6: being moulded in position" from "plastic material andso' as to form anionolith.

'Figure III shows much "the'sanie roofia's Figure I but with a hipped end foimatiohrincldding the half rafter members 11, "and the hip the ridge 1; '-and" the'-jack rlafterm'embers l 9 associated' with the diagonal hipraft'ermembers 1 3.

7 Another form "of differs frcm'tnate Figure'Ifby the omissionrof the ceiling slab3 and by the members""4 being supported difctly'on thewalls" 2. This figure also shows'thew'eb' "formation as'trertical and longi- "tudihal web's "extending btwnthe rafter members '4 f'orhiihg"witlfthe 'laltter acellular formation which combines lightness with consid- 1 erable stiffness.

In Figure V; the Figure Iariangementijnlodisea by omitting thetrsnsverse members a and substituting fdfthma'nu'mbr or lbl lgi udinal l walls or 'ribs 2|. Theraft'er function of uppo'r ting the ro'of c'ovrmg'at 'thepith an'g1eis in this case exercisedby "the combinationof the several walls 2| which for"- that 'purpb'se roi m -a serres progressively increasing in height fro e eaves roof, said walls 2| per-form th a'ddit-ibhal function of the purlins in an ordinary roof. )7

Figure VI showsa lean-to -typ'e 'o'ffrobf,-' wliich is structurally and functiohally eifual "w a lhgitudinal'half of Figure I I Roofs according to theihvei'itidn areerected with the "aid of shutteringj '=anda ty pical='n'ie'thod of using the shuttering-is illustrated"ifi Figures I, VII, IX and X.

The ceiling 'slab'3is iriduldedfin place'by spreading plastic concrete on deck shuttering "which is erected for the purpose andis afterwardsiremoved. A shuttering structure capable of rapid erection and removal is shown in-F-igure I. Re-

cesses 23ar'e provided at thet'ops of- -the'fwai'ls 2; and bearer bars 24 are -placedfin said' recesses 23 to span the s pa'ce between the walls. Dec ut- 511 said sers- 24;at"praviae tne'mserdmgsuifaceeswas 45 to che siwim'iegsmzses zupwsrawsosie {below the 'mouth 41 is' "steer greater *thatthe base surface 4'9; cdnnebting' th' recess shields 21 are placed over the recesses 23 to keep concrete out of the latter. Thereupon the plastic concrete is spread over said surface 26 to form the slab 3. When the concrete has set, the bars 24 are withdrawn endwise, permitting the deck shuttering 25 to fall or to be prized away from *the'concrete.

' The recesses 23 are deep enoug-h to enable the moulding surface 26 to be brought level with the upper surfaces 28 of the walls 2 or such other level as desired above the base surfaces 29 fof the recess 23. To facilitate the endwise withdieiwal of the bars 24, it is preferred to elevate theyare'shownas supported on wedges 30 that can be knocked out of place to drop the bar.

The intermediate bearer bars 24 are shown of T section with their cross flanges 3| below, forming horizontal shelves on which separate shuttering panels-32 are loosely rested.

The end bearer bars 24a are-of angle sectionl inorder that their vertical elements- 33 :may lie flat against the end wal1s9. The advantage :of using panels inthis waybetweenbearer bars is that the deck shuttering canbe erected by building -up' anumber of small-miita individuallycapable of being handled; and the shuttering-can be disassembled in the-same advantageous' manner.

After the ceiling slab "3 is: poured, shuttering is erected on it for mouldingthe-members 4 (Figure 'VII). In theexample' il-lustratedy the shuttering is of the kind described-in my application Serial No. 577,898, mow -=Patent No. 2,518,186, dated'August 8, 1950. It comprises pairs' 'of templet 'bars 34*which -arelaidon the ceiling slab 3and are connected and space'd a'part by ties 35. shuttering panels (lit-are :provided which are similar to those described in the specification of my applicationserial No. 583,269, now Patent No. 2,447,670, dated-"August 24, l94'8;-'except that they are' triangular tobnform to the gab'le shape of the 'membersfl. whe ipanels and the templet bars"are-"formed with he iriteren- -gaging "edge formations 3'I ,-33 by' which theipanels are retained in the upright posi'tion. 1 During the erection of the"shutterin :pazier cores ss a ins'ert'ed 'betw'e'en thein to I ane-apertures l l and furtherc'or'e's' 40 are inserted to form gaps -41 in the upper -eagle 5' cr me mem ers a,

"(Figure- 1X) arranged to waive our'id that are 'prefei'abl'y steel tubes" an "port the decks'huttering l l on hich tl' ie r'oof covering Bis moulded.

"Cess 45 is equal t "members 4. In th'e x tefision the extent. At least two such gaps 4| are formed on each downwardly sloping edge 5 of the membars 4.

In preparing for the moulding of the roof covering 6, the round bars 43 are laid to extend over the several gaps 4| of the different members 4 in the same horizontal series and to seat in the recesses 45. Deck shuttering 44 of such width as to fit neatly between the members 4 is laid on said bars 43 and the mouths 4! of the gaps 4| are shielded against the entrance of concrete by covers 50 of sheet material.

Plastic concrete is then spread over the deck shuttering 44 and the exposed edges 5 of the members 4. When the concrete has set the round bars 43 are rolled up into the recess extension 46 thereby allowing the deck shuttering 44 to drop or to be prized away from the underside of the hardened roof covering 6.

The deck shuttering 44 is withdrawn piecemeal from the interior of the roof for re-use, if it is suitable for such re-use, through openings provided for that purpose. In the example shown in Figures I and IX, the shuttering extends beyond the walls 2 of the building to provide the eaves of the roof and can therefore be withdrawn downward after separation from the roof covering. If the ceiling slab 3 is extended over the walls 2 to form an eaves soflit 5| Figure X, gapping 52 is left at the ridge of the roof for the withdrawal of the deck shuttering 44 upwardly. The missing ridge structure is afterwards completed as by ridge capping 53.

An important object of the invention is the construction of the roof as a monolithic structure combining light weight with stiffness as a girder.

When both the ceiling slab and the roof covering are moulded in position, the cross section of the roof resembles an I section girder; of which the ceiling slab 3 and the roof covering 6 are the bottom and top flanges and each rafter member 4 is the vertical element.

In order to utilize such girder formation to minimize the thickness of the concrete, it is important that the structure should be rendered monolithic to a high degree, as for instance by proper use of reinforcement to bond such sections together. ment includes elements such as 54 Figure I, that closely unite the slab 3 and the members 4;

In particular the reinforceand the elements III that unite the roof covering 6 to the members 4.

I claim:

1. The process of erecting a pitched roof with cast-on roof covering, which comprises the steps of supporting a plurality of longitudinally extending bars of circular section on the lower portions of bearing surfaces that diverge from the plane of the roof to be erected toward the ridge of the roof, positioning deck shuttering for the roof covering on said bars, casting the roof covering on said shuttering while leaving an opening in the roof for extraction of the deck shuttering, rolling the bars laterally along the bearing surfaces toward the ridge, lowering the deck shuttering to part it from the cast roof covering, and withdrawing the deck shuttering through the opening.

2. The process as set forth in claim 1 wherein the opening is formed at the ridge of the roof.

3. The process as set forth in claim 1 wherein the opening is formed at the ridge of the roof and further including the step of closing the opening after the shuttering has been withdrawn.

4. The process as set forth in claim 1 wherein the opening is formed adjacent the base of the roof.

5. The process as set forth in claim 1 further including the steps of lowering the bars after the shuttering has been withdrawn through the opening and withdrawing the bars from their bearing surface.

ROY WILLIAM RUMBLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,155,038 Broughton Sept. 28, 1915 1,185,871 Broughton June 6, 1916 1,261,125 Havens Apr. 2, 1918 1,465,166 Matthews Aug. 14, 1923 2,335,300 Neff Nov. 30, 1943 FOREIGN PATENTS Number Country Date 88,361 Sweden 193? 841,888 France 1939 

